/**
 * @class Ext.fx.Animator
 *
 * This class is used to run keyframe based animations, which follows the CSS3 based animation structure.
 * Keyframe animations differ from typical from/to animations in that they offer the ability to specify values
 * at various points throughout the animation.
 *
 * ## Using Keyframes
 *
 * The {@link #keyframes} option is the most important part of specifying an animation when using this
 * class. A key frame is a point in a particular animation. We represent this as a percentage of the
 * total animation duration. At each key frame, we can specify the target values at that time. Note that
 * you *must* specify the values at 0% and 100%, the start and ending values. There is also a {@link #keyframe}
 * event that fires after each key frame is reached.
 *
 * ## Example
 *
 * In the example below, we modify the values of the element at each fifth throughout the animation.
 *
 *     @example
 *     Ext.create('Ext.fx.Animator', {
 *         target: Ext.getBody().createChild({
 *             style: {
 *                 width: '100px',
 *                 height: '100px',
 *                 'background-color': 'red'
 *             }
 *         }),
 *         duration: 10000, // 10 seconds
 *         keyframes: {
 *             0: {
 *                 opacity: 1,
 *                 backgroundColor: 'FF0000'
 *             },
 *             20: {
 *                 x: 30,
 *                 opacity: 0.5
 *             },
 *             40: {
 *                 x: 130,
 *                 backgroundColor: '0000FF'
 *             },
 *             60: {
 *                 y: 80,
 *                 opacity: 0.3
 *             },
 *             80: {
 *                 width: 200,
 *                 y: 200
 *             },
 *             100: {
 *                 opacity: 1,
 *                 backgroundColor: '00FF00'
 *             }
 *         }
 *     });
 */
Ext.define('Ext.fx.Animator', {

    /* Begin Definitions */

    mixins: {
        observable: 'Ext.util.Observable'
    },

    requires: ['Ext.fx.Manager'],

    /* End Definitions */

    isAnimator: true,

    /**
     * @cfg {Number} duration
     * Time in milliseconds for the animation to last. Defaults to 250.
     */
    duration: 250,

    /**
     * @cfg {Number} delay
     * Time to delay before starting the animation. Defaults to 0.
     */
    delay: 0,

    /* private used to track a delayed starting time */
    delayStart: 0,

    /**
     * @cfg {Boolean} dynamic
     * Currently only for Component Animation: Only set a component's outer element size bypassing layouts.  Set to true to do full layouts for every frame of the animation.  Defaults to false.
     */
    dynamic: false,

    /**
     * @cfg {String} easing
     *
     * This describes how the intermediate values used during a transition will be calculated. It allows for a transition to change
     * speed over its duration.
     *
     *  - backIn
     *  - backOut
     *  - bounceIn
     *  - bounceOut
     *  - ease
     *  - easeIn
     *  - easeOut
     *  - easeInOut
     *  - elasticIn
     *  - elasticOut
     *  - cubic-bezier(x1, y1, x2, y2)
     *
     * Note that cubic-bezier will create a custom easing curve following the CSS3 [transition-timing-function][0]
     * specification.  The four values specify points P1 and P2 of the curve as (x1, y1, x2, y2). All values must
     * be in the range [0, 1] or the definition is invalid.
     *
     * [0]: http://www.w3.org/TR/css3-transitions/#transition-timing-function_tag
     */
    easing: 'ease',

    /**
     * Flag to determine if the animation has started
     * @property running
     * @type Boolean
     */
    running: false,

    /**
     * Flag to determine if the animation is paused. Only set this to true if you need to
     * keep the Anim instance around to be unpaused later; otherwise call {@link #end}.
     * @property paused
     * @type Boolean
     */
    paused: false,

    /**
     * @private
     */
    damper: 1,

    /**
     * @cfg {Number} iterations
     * Number of times to execute the animation. Defaults to 1.
     */
    iterations: 1,

    /**
     * Current iteration the animation is running.
     * @property currentIteration
     * @type Number
     */
    currentIteration: 0,

    /**
     * Current keyframe step of the animation.
     * @property keyframeStep
     * @type Number
     */
    keyframeStep: 0,

    /**
     * @private
     */
    animKeyFramesRE: /^(from|to|\d+%?)$/,

    /**
     * @cfg {Ext.fx.target.Target} target
     * The Ext.fx.target to apply the animation to.  If not specified during initialization, this can be passed to the applyAnimator
     * method to apply the same animation to many targets.
     */

     /**
      * @cfg {Object} keyframes
      * Animation keyframes follow the CSS3 Animation configuration pattern. 'from' is always considered '0%' and 'to'
      * is considered '100%'.<b>Every keyframe declaration must have a keyframe rule for 0% and 100%, possibly defined using
      * "from" or "to"</b>.  A keyframe declaration without these keyframe selectors is invalid and will not be available for
      * animation.  The keyframe declaration for a keyframe rule consists of properties and values. Properties that are unable to
      * be animated are ignored in these rules, with the exception of 'easing' which can be changed at each keyframe. For example:
 <pre><code>
keyframes : {
    '0%': {
        left: 100
    },
    '40%': {
        left: 150
    },
    '60%': {
        left: 75
    },
    '100%': {
        left: 100
    }
}
 </code></pre>
      */
    constructor: function(config) {
        var me = this;
        config = Ext.apply(me, config || {});
        me.config = config;
        me.id = Ext.id(null, 'ext-animator-');
        me.addEvents(
            /**
             * @event beforeanimate
             * Fires before the animation starts. A handler can return false to cancel the animation.
             * @param {Ext.fx.Animator} this
             */
            'beforeanimate',
            /**
              * @event keyframe
              * Fires at each keyframe.
              * @param {Ext.fx.Animator} this
              * @param {Number} keyframe step number
              */
            'keyframe',
            /**
             * @event afteranimate
             * Fires when the animation is complete.
             * @param {Ext.fx.Animator} this
             * @param {Date} startTime
             */
            'afteranimate'
        );
        me.mixins.observable.constructor.call(me, config);
        me.timeline = [];
        me.createTimeline(me.keyframes);
        if (me.target) {
            me.applyAnimator(me.target);
            Ext.fx.Manager.addAnim(me);
        }
    },

    /**
     * @private
     */
    sorter: function (a, b) {
        return a.pct - b.pct;
    },

    /**
     * @private
     * Takes the given keyframe configuration object and converts it into an ordered array with the passed attributes per keyframe
     * or applying the 'to' configuration to all keyframes.  Also calculates the proper animation duration per keyframe.
     */
    createTimeline: function(keyframes) {
        var me = this,
            attrs = [],
            to = me.to || {},
            duration = me.duration,
            prevMs, ms, i, ln, pct, anim, nextAnim, attr;

        for (pct in keyframes) {
            if (keyframes.hasOwnProperty(pct) && me.animKeyFramesRE.test(pct)) {
                attr = {attrs: Ext.apply(keyframes[pct], to)};
                // CSS3 spec allow for from/to to be specified.
                if (pct == "from") {
                    pct = 0;
                }
                else if (pct == "to") {
                    pct = 100;
                }
                // convert % values into integers
                attr.pct = parseInt(pct, 10);
                attrs.push(attr);
            }
        }
        // Sort by pct property
        Ext.Array.sort(attrs, me.sorter);
        // Only an end
        //if (attrs[0].pct) {
        //    attrs.unshift({pct: 0, attrs: element.attrs});
        //}

        ln = attrs.length;
        for (i = 0; i < ln; i++) {
            prevMs = (attrs[i - 1]) ? duration * (attrs[i - 1].pct / 100) : 0;
            ms = duration * (attrs[i].pct / 100);
            me.timeline.push({
                duration: ms - prevMs,
                attrs: attrs[i].attrs
            });
        }
    },

    /**
     * Applies animation to the Ext.fx.target
     * @private
     * @param target
     * @type String/Object
     */
    applyAnimator: function(target) {
        var me = this,
            anims = [],
            timeline = me.timeline,
            reverse = me.reverse,
            ln = timeline.length,
            anim, easing, damper, initial, attrs, lastAttrs, i;

        if (me.fireEvent('beforeanimate', me) !== false) {
            for (i = 0; i < ln; i++) {
                anim = timeline[i];
                attrs = anim.attrs;
                easing = attrs.easing || me.easing;
                damper = attrs.damper || me.damper;
                delete attrs.easing;
                delete attrs.damper;
                anim = new Ext.fx.Anim({
                    target: target,
                    easing: easing,
                    damper: damper,
                    duration: anim.duration,
                    paused: true,
                    to: attrs
                });
                anims.push(anim);
            }
            me.animations = anims;
            me.target = anim.target;
            for (i = 0; i < ln - 1; i++) {
                anim = anims[i];
                anim.nextAnim = anims[i + 1];
                anim.on('afteranimate', function() {
                    this.nextAnim.paused = false;
                });
                anim.on('afteranimate', function() {
                    this.fireEvent('keyframe', this, ++this.keyframeStep);
                }, me);
            }
            anims[ln - 1].on('afteranimate', function() {
                this.lastFrame();
            }, me);
        }
    },

    /**
     * @private
     * Fires beforeanimate and sets the running flag.
     */
    start: function(startTime) {
        var me = this,
            delay = me.delay,
            delayStart = me.delayStart,
            delayDelta;
        if (delay) {
            if (!delayStart) {
                me.delayStart = startTime;
                return;
            }
            else {
                delayDelta = startTime - delayStart;
                if (delayDelta < delay) {
                    return;
                }
                else {
                    // Compensate for frame delay;
                    startTime = new Date(delayStart.getTime() + delay);
                }
            }
        }
        if (me.fireEvent('beforeanimate', me) !== false) {
            me.startTime = startTime;
            me.running = true;
            me.animations[me.keyframeStep].paused = false;
        }
    },

    /**
     * @private
     * Perform lastFrame cleanup and handle iterations
     * @returns a hash of the new attributes.
     */
    lastFrame: function() {
        var me = this,
            iter = me.iterations,
            iterCount = me.currentIteration;

        iterCount++;
        if (iterCount < iter) {
            me.startTime = new Date();
            me.currentIteration = iterCount;
            me.keyframeStep = 0;
            me.applyAnimator(me.target);
            me.animations[me.keyframeStep].paused = false;
        }
        else {
            me.currentIteration = 0;
            me.end();
        }
    },

    /**
     * Fire afteranimate event and end the animation. Usually called automatically when the
     * animation reaches its final frame, but can also be called manually to pre-emptively
     * stop and destroy the running animation.
     */
    end: function() {
        var me = this;
        me.fireEvent('afteranimate', me, me.startTime, new Date() - me.startTime);
    }
});